Field
Embodiments described herein generally relate to apparatus and methods for improving gas delivery to a semiconductor processing chamber. More specifically, embodiments described herein relate to an upper dome with an injection assembly.
Description of the Related Art
In semiconductor processing, various processes are commonly used to form films that have functionality in a semiconductor device. Among those processes are certain types of deposition processes referred to as epitaxy. In an epitaxy process, a gas mixture is typically introduced in a chamber containing one or more substrates on which an epitaxial layer is to be formed. Process conditions are maintained to encourage the vapor to form a high quality material layer on the substrate. Epitaxy is generally favored when high quality and uniformity of a film deposited across the surface of a substrate are desired.
In an exemplary epitaxy process, a material such as a dielectric material or semiconductor material is formed on an upper surface of a substrate. The epitaxy process grows a thin, ultra-pure material layer, such as silicon or germanium, on a surface of the substrate. The material may be deposited in a lateral flow chamber by flowing a process gas substantially parallel to the surface of a substrate positioned on a support, and by thermally decomposing the process gas to deposit a material from the gas onto the substrate surface.
Processing uniformity is generally desired in the semiconductor industry, and much research and development effort is devoted to improving processing uniformity throughout the semiconductor fabrication process. Reactor design, for example, gas flow patterns and temperature control apparatus, can affect film quality and uniformity in epitaxial growth. Since gas flow characteristics can impact the film performance on the substrate, there is a need for a gas delivery and deposition apparatus which facilitates growth of a uniform material layer on the substrate.
Cross-flow gas delivery apparatuses inject gas into the processing chamber such that the gas flows laterally across the surface of the substrate while the substrate is rotated. However, center to edge non-uniformities of the deposited film may result due to uneven gas flow characteristics. In some cases, the type and number of precursor species that may be introduced via the cross-flow gas delivery apparatus are limited.
Thus, there is a need in the art for improved gas delivery apparatus for epitaxy processes.